Existing security systems are varied and, in many cases, easily bypassed or defeated. For example, it is not unusual for people to carry various different cards or devices to gain access to different locations or consummate transactions at various devices. Still further, people are notoriously bad at selecting security passwords that are easy to remember and hard to guess or defeat. Moreover, even where good passwords are used, it is possible to obtain a user's password through observation, keystroke capture, etc. and it is not unusual for users to be signed on to a secure system and then leave without logging out, (intentionally or unintentionally) relying upon inactivity to trigger logging out.
For people with physical limitations, whether involving problems with vision, hearing, mobility or dexterity, conforming to typical authentication protocols can be difficult or frustrating. Newer computers and smart phones have made it easier for people with limitations to perform certain actions, but they generally still rely upon whatever security system is in place for the device with which the user will interact. Thus, a visually impaired person can rely upon speech to text conversion to input a password, for example, but in such cases, security is generally lessened, not heightened.
Finally, in general, the type of authentication used for any given device tends to be universally applied for all users of that particular device, for example, a password, card key, fingerprint, etc., whenever it is used.